A conventional blade server comprises a case including a plurality of holes at the front of the case, a circuit board in the case and including an L-shaped connector having one end electrically connected to the circuit board and the other end electrically connected to a hard disk drive fixedly mounted on the circuit board, a plurality of fans at the rear of the case, the fans being adapted to drive air out of the case. In an operation of the blade server, the fans are activated to drive hot air caused by the operation out of the case. At the same time, external cold air is drawn into the case through the holes. A cold air current is thus formed and blown along a top surface of the circuit board. As a result, temperature on the top surface of the circuit board is decreased significantly to be in the range of operating temperature of the circuit board.
Moreover, the blade server is mounted on a chassis in its operating position. The most significant feature of the blade server is that a plurality of chipsets, electronic components, and interface devices are provided on the circuit board in its limited internal space of the case. Thus, the blade server has an improved performance as compared to other existing ones. However, high temperature can be generated by the chipsets, electronic components, and interface devices during operation. Further, as stated above the chipsets, electronic components, and interface devices are provided in the limited internal space of the case. As a result, the blade server tends to operate in an undesired overheat condition. Thus, it is important to consider how to carry out an effective heat dissipation in the design phase of the blade server.
Height of the case of blade server is 1 U equal to 1¾″ or 44.45 mm and height of the hard disk drive installed therein is 9.5 mm or 0.37″. Thus, cold air current flowing from the front to the rear of the case is blocked by the hard disk drive. This can undesirably decrease heat dissipation over the top surface of the circuit board. That is, cold air current cannot uniformly flow over the top surface of the circuit board. Hence, hot air is only partially driven out of the case. As a result, the total heat dissipation performance of the blade server is decreased greatly. And in turn, the blade server may operate abnormally or even malfunction. Thus, it is desirable to provide a blade server having improved connection arrangement for allowing cold air current to uniformly flow over the top surface of the circuit board so as to carry out the required heat dissipation of the circuit board and thus the blade server may not operate in an overheat condition.